Abstract: In the past two decades, cross-track interferometry has been used extensively for mapping surface topography and topographic change for applications as varying as solid earth science, cryospheric science, oceanography, and for determining the vertical structure of vegetation.The physical size of an interferometer is dominated by a baseline whose length is proportional to the wavelength of the carrier frequency.As such, in part to reduce the physical size of structures for spaceborne applications, there is a general trend to using high frequencies (X-band and higher) for single-pass interferometry.This paper discusses the results from the creation and testing of a high precision two-channel Ku-band downconverter development by the University of Massachusetts and the Jet Propulsion Laboratory.Lessons learned from the Ku-band development are currently being applied to a similar system operating at Ka-band.